1. Field of the Invention
The present invention relates to an optical disc recording/reproducing apparatus using a postscript type CD-R disc which can record music data and so forth.
2. Description of the Prior Art
Thus far, a postscript type CD which satisfies the optical standard of a CD (Compact Disc) and which can reproduce data which has been recorded thereon with a conventional CD player is becoming known. This type CD is hereinafter referred to as the CD-R. With this postscript type CD-R, a small number of CDs can be easily produced for specific purposes and personal use.
A CD is provided with a TOC (Table of Contents) at a lead-in area located on the outermost periphery thereof. In the TOC, data position information such as an absolute time at which each music program recorded on the disc starts, a first music program number, a last music program number, and an end time at which the last music program ends is recorded. In a conventional CD player, usually, this lead-in TOC is first accessed. Thus, the data position information is obtained. With this data position information, a pick-up is accessed to a desired music program position and a random access operation is performed.
With respect to the postscript type CD-R, so far the following techniques for recording TOC data have been proposed.
One of these techniques is referred to as the after-TOC technique. In this technique, all music programs to be recorded are recorded on a disc. After TOC data according to the recorded music programs has been designated, TOC data is recorded at the lead-in area. This after-TOC technique is disclosed in, for example, U.S. Pat. No. 4,931,927.
The other technique is referred to as the pre-TOC technique. In this technique, a TOC area has been recorded in advance so that music program areas are divided into segments of a predetermined time period. After the TOC data has been recorded, music data is recorded in accordance with the music program areas divided by the TOC data.
In the after-TOC technique, since the TOC data is recorded after the music data has been recorded and then the TOC data has been designated, the start time and end time of each music program which has been recorded accord with those designated with the TOC data. Thus, when a music program is reproduced, its start and end position can be easily accessed.
However, in the postscript type CD, the TOC data cannot be changed. Thus, in the after-TOC technique, even if a blank area is present in a record area where music data has been initially recorded, another music data cannot be recorded on a postscript basis. This is because the postscript music data causes the TOC to be changed. Thus, in the after-TOC technique, the record area is sometimes wastefully used.
On the other hand, in the pre-TOC technique, since a TOC which divides music data into segments of a predetermined time period has been recorded, a music data area for each music program has been provided in advance. Thus, on a disc where several music programs have been recorded, music data can be recorded on the postscript basis. However, in the pre-TOC technique, since the music data area is divided into segments of a predetermined time period, the time period of a music program which has been recorded does not sometimes match that designated with the TOC data. Thus, it becomes difficult to access the start and positions of each music program by using the TOC data.